524. A Series of False Positive 4th Generation Rapid HIV Tests in an Urban Labor and Delivery Setting
Session: Poster Abstract Session: HIV Testing and Diagnosis
Thursday, October 27, 2016
Room: Poster Hall
Background: Four women presented to University of Chicago Medicine (UCM) labor and delivery (L & D) between 1/13/16 and 2/2/16 and had positive HIV point-of-care tests, which were later found to be falsely positive. It is the policy of UCM L & D to perform rapid HIV testing on any woman without a documented HIV test during her current pregnancy.

Methods: All four women had a faintly positive rapid HIV test. None reported a history of HIV. Each woman received prenatal care at an outside facility. Two women were placed on intravenous zidovudine for prevention of mother-to-child HIV transmission and terbutaline to slow labor while awaiting the results of additional HIV testing. One of the women given terbutaline had a caesarian section because labor progressed prior to receiving results of additional testing. The infant of this patient was placed on triple antiretroviral therapy. In all four women, HIV 1/2 supplemental differentiation assays and HIV RNA PCRs were negative. Since the initiation of 4th generation rapid HIV 1/2 Ab/Ag testing in December 2015 at UCM, there were 6 false positive tests out of 137 performed (4.4%). In contrast, 17% of screening HIV enzyme immunoassay (EIA) tests sent from UCM are found to be discrepant when supplemental testing is performed. However, given the time sensitivity of HIV testing in an L & D setting, the false positive rate of 4.4% was felt to be unacceptably high, which prompted a change back to 3rdgeneration HIV rapid testing while additional data was gathered and assessments were made on the optimal process for HIV testing in L & D. Of note, pregnant women are more likely to have positive HIV EIA tests in the setting of a negative or indeterminate Western Blot.

Results: Efforts are underway to streamline HIV testing for patients in L & D at UCM by 1) decreasing time from arrival to rapid HIV test; 2) decreasing time from positive rapid HIV test to initiating supplemental testing; 3) bringing supplemental HIV differentiation testing on site to decrease time spent in sending out specimens; and 4) improving turnaround time of HIV RNA PCR test results. 

Conclusion: If HIV supplemental testing can be performed quickly after a positive rapid test, unnecessary interventions may be prevented, such as caesarian section, restriction of breast-feeding and use of antiretroviral medication for laboring women and neonates.

M. Ellen Acree, MD1, Kathleen G. Beavis, MD2, Angella Charnot-Katsikas, MD2, Kenneth Nunes, MD3 and Allison H. Bartlett, MD, MS4, (1)Department of Medicine, Section of Infectious Diseases and Global Health, The University of Chicago Medicine, Chicago, IL, (2)Department of Pathology, The University of Chicago Medicine, Chicago, IL, (3)Department of Obstetrics/Gynecology, The University of Chicago Medicine, Chicago, IL, (4)Department of Pediatrics, Section of Infectious Diseases, The University of Chicago Medicine, Chicago, IL

Disclosures:

M. E. Acree, None

K. G. Beavis, None

A. Charnot-Katsikas, None

K. Nunes, None

A. H. Bartlett, None

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.